Loneliness The most broadly accepted definition of loneliness is the

The most broadly accepted definition of loneliness is the distress that results from
discrepancies between ideal and perceived social relationships. This so-called cognitive
discrepancy perspective makes it clear that loneliness is not synonymous with being alone, nor
does being with others guarantee protection from feelings of loneliness. Rather, loneliness is the
distressing feeling that occurs when one’s social relationships are perceived as being less
satisfying than what is desired. This entry describes how loneliness is conceived and measured;
how loneliness is mentally represented; how loneliness influences thoughts, feelings, and
behaviors; and consequences of loneliness for health and wellbeing.
Despite general agreement over its definition, loneliness is conceived in a number of ways.
One theory of loneliness holds that deficiencies in specific provisions of social relationships
contribute to specific types of lonely feelings. For instance, lack of engagement in a social
network is associated with feelings of social loneliness such as aimlessness, boredom, and
exclusion. On the other hand, absence of a reliable attachment figure (e.g., spouse) is associated
with feelings of emotional loneliness such as anxiety, desolation, and insecurity. More recent
studies have shown that these types of lonely feelings are not uniquely associated with certain
relationships, however. Marriage, for example, serves a broad social integrative function that
diminishes feelings of both social and emotional loneliness, especially for women.
Another theory holds that loneliness arises from social skill deficits and personality traits
that impair the formation and maintenance of social relationships. Social skills research has
shown that loneliness is associated with more self-focus, poorer partner attention skills, a lack of
self-disclosure to friends, especially among females, and less participation in organized groups,
especially among males. Personality research has shown that loneliness is associated with
p. 2 shyness, neuroticism, and depressive symptoms, as well as low self-esteem, pessimism, low
conscientiousness, and disagreeableness. Associations among these characteristics have
sometimes led to conceptual confusion between loneliness and depressed affect, poor social
support, introversion, and/or neuroticism. Research indicates, however, that loneliness, although
related, is independent of these characteristics both conceptually and operationally (i.e., the
measurement tools for each of these characteristics are relatively specific for the corresponding
traits). Moreover, the effects of loneliness on physical health and physiology are generally not
explained by the behavioral and personality characteristics with which loneliness is associated,
indicating that loneliness may be a unique psychosocial risk factor whose effects are
distinguishable from some combination of poor social support, depression, and personality traits.
Loneliness is aversive, but that is not necessarily a bad thing. An evolutionary
conceptualization of loneliness holds that the aversive feelings are adaptive because they
motivate the repair or replacement of social connections. Human offspring are born to the
longest period of utter dependency of any species. Simple reproduction, therefore, is not
sufficient to ensure that one’s genes make it into the gene pool. For one’s genes to make it to the
gene pool, these offspring must survive to reproduce. Social connections and the behaviors they
engender (e.g., cooperation, altruism, alliances) enhance the survival of the parents and,
consequently, their children are more likely to survive to reproduce..
In early human history, hunter-gatherers whose genetic predisposition encouraged
social/family “togetherness” and the offering of food and protection to mother and child would
have increased offspring survival odds, whereas hunter-gatherers who felt no compunction about
ignoring social/family bonds would have reduced the survival odds of their offspring. The latter
may have survived to have another family, however, suggesting that no single genetic
p. 3 predisposition is superior. The consequences of such an evolutionary scenario would be heritable
individual differences in loneliness, and adoption and twin studies among children and adults
support this view. Approximately 48% of the variability in loneliness levels can be explained by
inherited tendencies to experience loneliness.
The genes underlying loneliness do not act alone. Interactions with the environment bring
the expression of an individual’s genes to the fore. The genetic biases that account for people’s
differing sensitivity to the social pain of isolation or rejection, and/or their differing propensity to
extract social “nutrients” from the environment, help to determine whether a given social context
will dampen or intensify a tendency to feel lonely.
Some social circumstances are fairly uniformly associated with an increased tendency
toward loneliness. Marriage is associated with the lowest levels of loneliness; loneliness is
greater among those who have experienced divorce and widowhood. Situational factors that
influence the availability of social opportunities are also associated with loneliness (e.g.,
geographic relocation). Social relationship quality is a more potent predictor of loneliness than
the existence or quantity of social contacts, however. Relationships that offer security, comfort,
trust, and pleasure, even if interactions are relatively infrequent, are much more effective at
preventing feelings of loneliness than are more friends or more frequent interactions that feel to
meet these standards. Even in marriage, , the quality of the relationship determines the degree of
protection against loneliness.
Lonely feelings are typically measured using a variety of items that assess the degree to
which respondents endorse thoughts and feelings characteristic of loneliness (e.g., “I feel alone,”
“I lack companionship,” “I do not feel part of a group of friends”). The result is a continuum in
p. 4 which the intensity and/or frequency of lonely feelings can range from very low (i.e., equivalent
to feelings of social connectedness) to very high. On average, lonely feelings are low to
moderate in the general population with only a relatively small percentage of individuals
experiencing intense lonely feelings at any given time. When asked simply whether or not they
are currently feeling lonely, approximately twenty percent of the population will respond
Social cognition.
Mental representations.
An axiom in the study of human relationships is that we are highly social animals.. A sense
of social connectedness is as vital to our survival as food and drink, yet is so taken for granted
that only the absence of that sense has been assigned a unique term. This suggests that “not
lonely” is the normal or default state required to maintain a healthy and balanced life and that
loneliness is the problematic state. Indeed, people’s mental representations of their sociality
conform to the importance of social bonds at every level of human endeavor.
Studies of loneliness have shown that mental representations of our connections with others
are characterized by individual, relational, and collective dimensions. These dimensions
correspond to individual, relational, and collective selves posited by theories of the self. At the
individual level, feelings of isolation and low self-worth are precluded when people feel
comfortable with themselves and their fit in a social world. At the relational level, feelings of
interpersonal connectedness are fostered in close dyadic relationships. At the collective level,
feelings of group identification and cohesion satisfy a need for belonging. This threedimensional representation of loneliness holds in young adults and across gender and
p. 5 racial/ethnic lines in middle age adults, suggesting a universality to this representational structure
of the social self.
Mental processes and behaviors.
Loneliness can be experienced acutely, as a temporary state that resolves when life
circumstances resolve (e.g., new friends are made in a new community), and chronically, as a
trait-like characteristic that results from an interaction between life circumstances and a genetic
bias to experience feelings of isolation. Once loneliness is triggered, it generates a defensive
form of thinking—a “lonely” social cognition—that can make every social molehill look like a
mountain. Lonely people tend to be more anxious, pessimistic, and fearful of negative evaluation
than people who feel good about their social lives, and are therefore more likely to act and relate
to others in ways that are anxious, negative, and self-protective, which leads paradoxically to
self-defeating behaviors. For instance, lonely and nonlonely individuals were equally likely to
cooperate with a stranger at the outset and during the early trials of a prisoner’s dilemma game in
which the stranger was playing a tit-for-tat strategy (i.e., cooperation met with cooperation,
betrayal with betrayal). This strategy resulted in an increase in cooperation across trials among
nonlonely subjects but not among lonely subjects. Similarly, self-reports showed that, relative to
nonlonely individuals, lonely individuals were less trusting of others and believed that they were
less trusted by others. In essence, lonely individuals exercised self-protective behaviors that
prevented them from enjoying the positive, cooperative interactions that were theirs to be had.
Not only do the lonely contribute to their own negative reality, but others begin to view them
more negatively and begin to act accordingly. One study showed that individuals told that an
opposite gender partner they were about to meet was lonely, subsequently rated that partner as
being less sociable. The individuals primed to have these expectations also behaved toward their
p. 6 partners in a less sociable manner than they did toward partners whom they expected to be
nonlonely. Once this negative feedback loop starts rolling, the cycle of defensive behavior and
negative social results spins even further downhill. The lonely not only react more intensely to
everyday hassles (e.g., misplacing or losing things), they experience less of an uplift from
everyday perks (e.g., meeting one’s responsibilities) than the nonlonely. In essence, lonely
individuals inhabit an inhospitable social orbit that repels others or elicits their negative
responses. Even when they succeed in eliciting nurturing support from a friend or loved one,
they tend to perceive the exchange as less than fulfilling.
Social rejection is a potent cause of loneliness, and the lonely tend to have a heightened
sensitivity to cues of social rejection and acceptance in their environment.. For instance, after
being presented with autobiographical information (i.e., ostensible diary entries) about a number
of individuals, lonely participants remembered a greater proportion of information related to
interpersonal or collective social ties than did nonlonely participants. It made no difference
whether the detail was emotionally positive or negative. In another study, participants asked to
“relive” a rejection experience, a procedure that increases feelings of loneliness, showed greater
attention to emotional vocal tone (i.e., a cue for social rejection or acceptance) in a subsequent
task than did participants asked to relive more neutral experiences.
Greater attention to social cues does not ensure greater social skills, however. Lonely
individuals are less accurate than nonlonely people at decoding facial and postural expressions of
emotion, for instance. A lack of correspondence between attention and accuracy in responses to
social cues has also been demonstrated in a brain imaging study of lonely and nonlonely young
adults. When presented with equally arousing positive and negative pictures of scenes and
objects (nonsocial stimuli) and people (social stimuli), activation in a set of brain regions often
p. 7 associated with visual attention and perspective taking varied in response to negative social (in
contrast to matched nonsocial) pictures. Relative to the nonlonely, lonely individuals showed
greater visual cortical activation (consistent with greater attention to the negative social than
nonsocial pictures) and less activation of the temporo-parietal junction (consistent with less
attention devoted to the other person’s perspective). Another set of brain regions, associated with
reward systems (i.e., ventral striatum), was found to be down-regulated in lonely, compared to
nonlonely, individuals when viewing positive social (in contrast to matched nonsocial) pictures –
results consistent with the idea that lonely individuals derive less pleasure than nonlonely
individuals from viewing positive social circumstances. This latter result may bear on the finding
that lonely individuals find positive social interactions during the course of a normal day less
satisfying than nonlonely individuals.
So although people may become lonely because of a genetic disposition coupled with an
unfortunate situation, they remain lonely because of the manner in which they and others think.
One might expect that a lonely person, hungry to fulfill unmet social needs, would be very
accepting of a new acquaintance. However, when confronted with an opportunity to form a
social connection, studies show that the lonely are actually far less accepting of potential new
friends than are the nonlonely. Similarly, in other studies, lonely students were less responsive to
their classmates during class discussions, and provided less appropriate and less effective
feedback than nonlonely students. Lonely undergraduates also held more negative perceptions of
their roommates than did the nonlonely, and this perceptual divide widened as one moved from
roommates to suitemates to floor mates to dorm mates.
Time also plays a role in constructing negative “realities.” Researchers asked participants to
interact with a friend, and to rate the quality of the relationship and the communication
p. 8 immediately, after watching a videotape of the same social exchange, a few weeks later after
being reminded of the interaction, and after again watching the videotape. At all four
measurement points, lonely individuals rated relationship quality more negatively than did
nonlonely individuals. Interestingly, the further in time they were removed from the social
exchange, the more negatively they rated it. Thus, the more time that passed, the more the
objective reality succumbed to the “reality” constructed by the lonely individual’s negative social
The loneliness continuum revisited
When loneliness is considered on a continuum that ranges from not at all to very, it is easy to
assume that social cognitive and behavioral characteristics differ in degree commensurate with
the degree of loneliness. However, individuals who experience few or no feelings of loneliness
are characterized by a unique and adaptive profile that is not simply the opposite of the profile of
highly lonely individuals. This was evident in a study of three groups of young adults selected
from a sample of more than 2,500 undergraduate students to represent loneliness scores in the
bottom 20% (low loneliness), middle 20% (average loneliness), and top 20% (high loneliness).
Individuals low in loneliness differed from individuals average or high in loneliness on four of
five personality dimensions (more outgoing, agreeable, conscientious, and non-neurotic), and
scored higher in optimism, positive mood, social skills, self-esteem, and social support, and
lower in anger, anxiety, shyness, fear of negative evaluation, and negativity. However,
individuals average or high in loneliness were indistinguishable on these scales.
These results do not mean that those who are low in loneliness possess characteristics that
render them immune to ever feeling lonely. Rather, when individuals feel socially connected,
they express a constellation of states and dispositions that enriches their lives not only
p. 9 quantitatively but also qualitatively relative to individuals who are average or high in loneliness.
That is, there seems to be something special about being and feeling socially connected. This
interpretation is supported by data from a hypnosis study in which young adults were made to
feel lonely and then socially connected (or vice versa, in a counterbalanced order) by recalling a
time when they felt rejected and like they didn’t belong, or accepted and like they belonged.
Measures of affect, social factors, and even personality traits mirrored and tracked the acute
changes in loneliness induced by the hypnotic manipulation. Participants induced to feel socially
connected, compared to lonely, reported significantly less negative mood, higher self-esteem and
optimism, better social skills, social support, and sociability, greater extraversion and
agreeableness, and less shyness, anxiety, anger, fear of negative evaluation, and neuroticism.
This experimental study suggests that loneliness has features of a central trait—central in the
sense that it influences how individuals construe themselves and others, and by extension, how
others view and act toward these individuals. Thus, although objective social circumstances (e.g.,
bereavement, ostracism) can modify feelings of loneliness, subjective social factors operate to
keep people in a lonely or socially connected state of being. Whereas lonely individuals think
about and behave toward others in a way that tends to reinforce a isolated existence, socially
connected individuals hold a more favorable view of others that in turn tends to reinforce their
being perceived and treated positively.
Health consequences
As this profile reveals, when loneliness takes over someone’s life, they become trapped in a
feedback loop of negative expectations, interpretations, and interactions. The challenge is
reframing and redirecting social perceptions so that a sense of meaningful social connectedness
can be established or recovered. Fortunately, the same feedback loop that allows individuals to
p. 10 construct a negative, subjective reality can be redirected to construct a better objective reality.
This could be particularly important given the health consequences of loneliness.
Loneliness has been associated with alterations in the functioning of the cardiovascular,
endocrine, and immune systems. A recent theoretical model of the correlates and consequences
of loneliness posits that age-related declines in physiological resilience are accelerated by
chronic loneliness. Accordingly, in younger adults, loneliness has been associated with early
markers of disease processes (e.g., subtle alterations in blood pressure control mechanisms),
whereas in older adults, loneliness has been associated with frank disease (e.g., elevated blood
pressure) and dysregulation across multiple physiological systems (e.g., impaired immune
functioning and elevated levels of stress hormones). Clearly, the costs of loneliness are too great
to ignore.
p. 11 Louise C. Hawkley & John T. Cacioppo
Center for Cognitive & Social Neuroscience & the Department of Psychology
University of Chicago
See Also
Attachment theory
Need for belonging
Self-monitoring and relationships
Social isolation
Further Readings
Boomsma, D. I., Willemsen, G., Dolan, C. V., Hawkley, L. C., & Cacioppo, J. T. (2005).
Genetic and environmental contributions to loneliness in adults: The Netherlands Twin
Register Study. Behavior Genetics, 35, 745-752.
Brewer, M.B., & Gardner, W. (1996). Who is this ‘‘we’’? Levels of collective identity and self
representations. Journal of Personality and Social Psychology, 71, 83–93.
Cacioppo, J. T., Hawkley, L. C., Ernst, J. M., Burleson, M. H., Berntson, G. G., Nouriani, B., &
Spiegel, D. (2006). Loneliness within a nomological net: An evolutionary perspective.
Journal of Research in Personality, 40, 1054-1085.
Dykstra, P. A., & Fokkema, T. (2007). Social and emotional loneliness among divorced and
married men and women: Comparing the deficit and cognitive perspectives. Basic and
Applied Social Psychology, 29, 1-12.
p. 12 Epley, N., Waytz, A., & Cacioppo, J. T. (2007). On seeing human: A three-factor theory of
anthropomorphism. Psychological Bulletin, 114, 864-886.
Ernst, J. M., & Cacioppo, J. T. (1998). Lonely hearts: Psychological perspectives on loneliness.
Applied & Preventive Psychology, 8, 1-22.
Gardner, W. L., Pickett, C. L., Jeffries, V., and Knowles, M. (2005). On the outside looking in:
Loneliness and social monitoring. Personality and Social Psychology Bulletin, 31, 15491560.
Hawkley, L. C., & Cacioppo, J. T. (2007). Aging and loneliness: Downhill quickly? Current
Directions in Psychological Science, 16, 187-191.
Peplau, L. A., & Perlman, D. (1982). Perspectives on loneliness. In L. A. Peplau & D. Perlman
(Eds.), Loneliness: A Sourcebook of Current Theory, Research and Therapy (pp. 1-20).
New York: John Wiley & Sons.
Pinquart, M., & Sörensen, S. (2003). Risk factor for loneliness in adulthood and old age – A
meta-analysis. In S. P. Shohov (Ed.), Advances in Psychology Research, Vol. 19 (pp.
111-143). Hauppauge, NY: Nova Science Publishers.
Weiss, R. S. (1973). Loneliness: The experience of emotional and social isolation. Cambridge,
MA: MIT Press.